The invention relates to a control device, in particular for automotive engineering, with a housing, a printed circuit board, on which surface-mountable components are soldered, and a plug-in connector, and to a method of soldering a wired component and SMT components onto a printed circuit board.
To meet the increasingly higher demands expected of the electrical functions and low-cost production of control devices in automotive engineering, discrete, powerful electrical components are increasingly being used in control circuits. However, these components often do not exist as surface-mountable components (SMD) or are only available at a far higher price than comparable wired components.
When additional wired components are used, the part of the printed circuit board loaded with SMT components is soldered by means of a reflow soldering method, and the wired components are soldered in a separate soldering process. However, various discrete components, for example electrolytic capacitors, cannot be exposed to the high temperatures which occur during reflow soldering. What is more, an additional soldering process is undesired in principle.
German published patent application DE 197 06 790 A1 discloses a control device with a printed circuit board that is loaded partly with surface-mountable components and partly with wired components. For this purpose, an opening is provided in a housing wall that must be sealed from environmental influences. On the outer side of the housing, this results in an elevation, which may hinder assembly.
European published patent application EP 0 854 666 A2 relates to a control device with a housing, in which surface-mountable components are soldered on a printed circuit board, and with a plug-in connector. A wired component is arranged near the plug-in connector. For this purpose, the housing cover has a side wall and an edge protruding beyond the plug-in connector and the wired component.
German published patent application DE 41 10 579 A1 discloses a plug-in connector for electronic control devices in motor vehicles, in which, to counter disturbing electromagnetic influences, components are attached to the outer side of the plug-in connector.
U.S. Pat. No. 5,444,416 discloses a digital demodulation device, in which, to counter disturbing influences, wired components are attached by printed circuit board in a cavity of the plug-in connector.
Finally, U.S. Pat. No. 5,712,765 discloses an electronics module with a housing, a printed circuit board, and a plug-in connector. The plug-in connector is fastened in the assembled state on the printed circuit board and receives an electronic component arranged on the printed circuit board in order to improve the heat dissipation from the electronic component. The electronic components are thereby arranged on the printed circuit board before the assembly of the plug-in connector and subsequently soldered, so that the assembly of the plug-in connector and the preassembly of the electronic components on the printed circuit board form separate working steps.
It is accordingly an object of the invention to provide a control device and a soldering method, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which provide for a control device and a method of soldering at least one wired component and surface-mountable components onto a printed circuit board which make it possible for control devices to be produced in an efficient, low-cost way which saves installation space.
With the foregoing and other objects in view there is provided, in accordance with the invention, a control device, comprising:
a housing;
a circuit board with surface-mounted components soldered thereto;
a plug-in connector having contact pins;
a plug-in connector housing formed with a cavity and a wired component disposed in the cavity and fastened to the plug-in connector housing, the wired component having connecting wires;
the plug-in connector having a centering aid with a grid for the contact pins of the plug-in connector and for connecting wires of the wired component.
With the above and other objects in view there is also provided, in accordance with the invention, a method of soldering wired components and surface-mountable components on a printed circuit board. The method comprises:
loading a printed circuit board with surface-mountable components;
fitting a wired component into a plug-in connector;
placing the plug-in connector on the printed circuit board such that contact pins and connecting wires of the wired component protrude through the printed circuit board; and
soldering the contact pins, the connecting wires, and the surface-mountable components onto the printed circuit board in a common process step.
Preferably, the method sequence comprises firstly fitting the wired component into a component housing and subsequently fitting the component housing into the plug-in connector.
By accommodating one or more wired components in the plug-in connector housing, it is possible to dispense with a separate placement of the wired component or components on the printed circuit board. A wired component is fitted together with the contact pins of the plug-in connector in corresponding plated through holes of the printed circuit board.
In a particularly preferred embodiment, a wired component is encapsulated by the plug-in connector housing, so that components which are not suitable for the very high temperatures occurring during a reflow soldering method can nevertheless be soldered at temperatures of 200xc2x0 C. and above. In this way, for example, electrolytic capacitors which may be exposed to a maximum temperature of 125xc2x0 C. can be soldered in a reflow soldering furnace.
Accommodating the wired component in the plug-in connector allows the surface area of the printed circuit board to be reduced. This is particularly advantageous if a printed circuit board can only be loaded on one side, in order for example to be brought into contact with a heat sink on one side. If in this case the printed circuit board is attached with one side to a housing inner wall and the plug-in connector is attached on the housing outer wall facing away from the printed circuit board, a particularly compact housing with a small enclosed air volume can be realized. For this purpose, the surface-mountable components (SMD) and the wired component are ideally soldered onto the same printed circuit board.
The plug-in connector housing may be formed in one piece with the housing wall or the housing cover. If a metallic, metallized or conductive material is used, particularly good shielding of the control device with respect to electro-magnetic interferences can be achieved.
The invention is particularly suitable for use in control devices of motor vehicles, and in particular for engine control devices.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a control device and soldering method, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.